Refactor file writing - rewrite crypto/opensslconf.h.in as template

The turn has come to have crypto/opensslconf.h.in get run through
util/dofile.pl.  The consequence is that a large number of variables
get moved to the %config table.

Also, the string variables $openssl_*, which were populated with cpp
lines, all being of the form "#define SOMETHING", were converted into
ARRAY refs in %config values, containing just the list of macros to be
defined.

Reviewed-by: Rich Salz <rsalz@openssl.org>